Project description:Sporadic Creutzfeldt-Jakob disease (sCJD) presents as a rapidly progressive dementia which is usually fatal within six months. No clinical blood tests are currently available for diagnosis or disease monitoring. Here, we profiled blood microRNA (miRNA) expression in sCJD. Small RNA-sequencing of 57 sCJD patients and 48 healthy controls revealed differential expression of hsa-let-7i-5p, hsa-miR-16-5p, hsa-miR-93-5p and hsa-miR-106b-3p. Downregulation of hsa-let-7i-5p, hsa-miR-16-5p and hsa-miR-93-5p replicated in an independent cohort using quantitative PCR, with concomitant upregulation of four of their mRNA targets. Absence of correlation in cross-sectional analysis with clinical phenotypes paralleled the lack of association between rate of decline in miRNA expression and rate of disease progression in a longitudinal cohort of 50 samples from 21 sCJD patients. Finally, the miRNA signature showed a high level of accuracy in discriminating sCJD from Alzheimer’s disease (AD). These findings highlight novel molecular alterations in the periphery in sCJD which can provide information about differential diagnosis and improve mechanistic understanding of human prion diseases.
Project description:Neuroinflammation is an essential part of neurodegeneration. Yet, current understanding of neuroinflamma-tion associated molecular events in distinct brain regions of prion disease patients is insufficient to lay the ground for effective treatment strategies targeting this complex neuropathological process. To address this problem, we analyzed expression of 800 neuroinflammation associated genes to create a profile of biological processes taking place in frontal cortex and cerebellum of patients, who suffered from sporadic Creutzfeldt-Jakob disease. The analysis was performed using NanoString nCounter technology, human neuroinflamma-tion panel+. The observed gene expression patterns indicate regionally, and sub-regionally common and dis-tinct molecular pathways associated with sporadic Creutzfeldt-Jakob disease pathogenesis. Moreover, the data show that the neuroinflammatory response in samples from the same brain region is variable. Based on the gene expression profiles from FC and CB, regional, neuroinflammatory patterns were observed.
Project description:Prion diseases are fatal and transmissible neurodegenerative disorders caused by the misfolding and aggregation of prion protein. Although recent studies have implicated epigenetic variation in common neurodegenerative disorders, no study has yet explored their role in human prion diseases. Here we profiled genome-wide blood DNA methylation in the most common human prion disease, sporadic Creutzfeldt-Jakob disease (sCJD). Our case-control study (n=219), when accounting for differences in cell type composition between individuals, identified 38 probes at genome-wide significance (p < 1.24x10-7). Nine of these sites were taken forward in a replication study, performed in an independent case-control (n=186) cohort using pyrosequencing. Sites in or close to FKBP5, AIM2 (2 probes), UHRF1, KCNAB2, PRNP, ANK1 successfully replicated. The blood-based DNA methylation signal was tissue- and disease-specific, in that the replicated probe signals were unchanged in case-control studies using sCJD frontal-cortex (n=84), blood samples from patients with Alzheimer’s disease, and from inherited and acquired prion diseases. Machine learning algorithms using blood DNA methylation array profiles accurately distinguished sCJD patients and controls. Finally, we identified sites whose methylation levels associated with prolonged survival in sCJD patients. Altogether, this study has identified a peripheral DNA methylation signature of sCJD with a variety of potential biomarker applications.
Project description:The familial or genetic Creutzfeldt-Jakob disease (fCJD or gCJD) is the inherent form of human prion diseases, which accounts for approximately 10-15% of human prion diseases that are caused by mutations of the prion protein gene (PRNP). In this study, the global expression patterns of the parietal cortex from a patient with G114V gCJD were comparatively analyzed with the normal controls by using a commercial human genome expression chip. Totally 8774 genes showed differential expression, among them 2769 genes were upregulated and 6005 ones were downregulated. The reliability of the results was confirmed by the real-time RT-PCR assays for several specific genes. The most differentially expressed genes involved in the functions of regulation of transcription, ion transport, transcription, cell adhesion, signal transduction. The gene associated with gliosis was upregulated and the genes marked for neurons were downregulated, while the transcription of PRNP gene maintained unchanged. 169 different pathways showed significantly changed in the brain of G114V gCJD. The most significantly regulated pathways included that of Alzheimer’s and Parkinson’s disease, oxidative phosphorylation, regulation of actin cytoskeleton, MAPK signaling pathway and proteasome, which were described in prion diseases previously. In addition, some rarely addressed pathways in prion diseases, such as axon guidance, gap junction and purine metabolism, were also significantly changed in G114V gCJD. The transcriptional situations of the most genes in the top ten changed pathways were down-regulated. The extensive reductions of gene expressions in G114V gCJD showed the comparable profiles with sporadic CJD. The data here raised the useful clues for understanding the pathogenesis of the disease and selecting the potential biomarkers for diagnostic and therapeutic tools. Brain tissues of parietal cortex from a definitely diagnosed G114V gCJD were enrolled into this study. The patient was a 47-year-old Han-Chinese woman at the onset. Neuropathological assays of ten different brain regions revealed typical sCJD-like abnormality and PrPSc deposits. Meanwhile, a commercial normal human parietal cortex total RNA (Clontech) pooled from four male/female aged 35-89 was utilized as control.